FIG. 22 shows a prior art bill validator 100 capable of detecting a plurality of optical features of valuable papers or bills by means of lights penetrating or reflected on bills. Validator 100 comprises a conveyer device 102 for transporting a bill 50 inserted into an inlet 101 along a passageway 55, a sensor device 110 for detecting optical and magnetic features of bill 50 traveling along passageway 55, and a control device 103 for receiving outputs from sensor device 110 to decide authenticity of bill 50 and also forward drive signals to conveyer device 102. A frame 104 comprises upper and lower casings 104a and 104b to accommodate conveyer device 102, sensor device 110 and control device 103 therein.
Not shown in the drawings, however, control device 103 comprises a memory that has previously stored information on patterns of light amount transmitted through and reflected on bill and magnetic pattern of bill, and a central processing unit (CPU) for comparing bill information output from sensor device 110 with stored bill information in the memory to decide kinds of bill 50 and authenticity of bill in accordance with agreement or disagreement between detected and stored information and also to control drive of conveyer device 102. Sensor device 110 comprises an optical sensor 111 for photo-electrically detecting optical features of bill 50 to produce detection signals and a magnetic sensor 112 for magneto-electrically detecting magnetic ink features printed in a predetermined area of bill 50 to produce detection signals. CPU 103 compares detection signals received from optical and magnetic sensors 111, 112 with stored signals in memory to decide authenticity or false of bill 50. When detection signals agree with signals in memory, CPU 103 decides bill 50 as genuine to further drive conveyer device 102, and bill 50 is further moved through an outlet 106 to stow it in a stacking chamber 105. To the contrary, when detection signals do not agree with signals in memory, CPU 103 decides bill 50 as false to drive conveyer device 102 in the adverse direction, and bill 50 is returned to inlet 101. A bill validator of the foregoing type is shown for example in U.S. Pat. No. 7,182,197.
In the bill validator 100 seen in FIG. 23, optical sensor 111 comprises photocouplers made up of light emitting diodes 114 and photo-transistors 115 deployed in the vicinity of and on the opposite sides of passageway 55 and in a vertically spaced relation to each other. Each of light emitting diodes 114 and photo-transistors 115 has a plastic shell 114a, 115a and outer leads or pins 117 extended from plastic shell 114a, 115a to mount them on upper and lower printed circuit boards 116 in frame 104 inserting and fastening pins 117 in through-halls on printed circuit boards 116. Each of light emitting diodes 114 and photo-transistors 115 has a hemi-spherical lens formed at the tip of plastic shell 114a, 115a, and cylindrical lenses 118 are disposed opposite to hemi-spherical lenses of plastic shell 114a, 115a. 
Optical sensor devices of this type are shown in for example U.S. Pat. Nos. 5,381,019; 5,903,339; and 7,242,796; and Japanese Utility Model Registration No. 3,037,946.
Such a prior art optical sensor device of the pin-insertion type however is disadvantageous because a plurality of light emitting diodes cannot be mounted in their accurate vertical and horizontal positions on printed circuit boards due to various or diversified shapes of outer leads or uneven or different attachment positions of outer leads in through-holes of printed circuit boards. This results in deviation of a light emission axis of light emitting diodes from a correct optical axis upon attachment on printed circuit boards while impeding an exact and effective detection of optical features from bills because light emitting diodes cannot correctly and precisely irradiate lights on predetermined target points on bill. There is also another defect in the prior art optical sensor device because plastic shell and outer leads extended from plastic shell cause height and thickness in sensor device to undesirably increase. Also, the more number of optical sensing elements is increased to improve detection accuracy of transmitted-light amount pattern, the more the occupation area of sensor device expands, thereby causing bill validator to be made in inconveniently larger size. Moreover, the prior art sensor device necessarily needs cylindrical lenses for light emitting diodes and light receiving transistors in addition to their hemi-spherical lenses. In this case, error in manufacture of sensor device would fluctuate light beams from light emitting diodes, and this may have a bad impact on uniform light beams. In another aspect, the inventors of the present invention firmly believe that one of modern bill validation techniques would pick out multicolored data of lights penetrated through many microscopic areas of a bill and then to precisely decide whether differences or rates between optical outputs in different wavelength are within or out of a predetermined range.
Accordingly, an object of the present invention is to provide a document photosensor capable of detecting a plurality of optical features of a document for improvement in detection performance of light amount patterns penetrated through the document. Another object of the present invention is to provide a document photosensor that has less number of light receiving elements capable of receiving lights of different wavelength irradiated from increased number of light emitting elements for improvement in validation performance. Still another object of the present invention is to provide a document photosensor in small size that comprises light emitting and receiving elements disposed at a reduced interval therebetween with the light emitting elements also disposed at a reduced interval therebetween for detecting a plurality of optical features of the document.